Zamil MAC-240, Installation, Operation & Maintenance Manual

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The scroll compressor consists of two involutes or Archimedean spirals. One spiral is positioned inside the other to form
a series of crescent-shaped pockets. During compression the upper spiral remains stationary and the lower one, being
eccentrically mounted on the drive shaft, describes an orbital rather than a simple rotary motion.
How a Scroll Compressor works:
Compression in the scroll is created by the interaction of an orbiting spiral and a stationary
spiral. A refrigerant enters the outer openings as one of the spirals orbits.
The open passages are sealed off as gas is drawn into the spiral.
As the spiral continues to orbit, the gas is compressed into two increasingly smaller pockets.
By the time the gas arrives at the center port, discharge pressure has been reached.
Actually, during operation, all six gas passages are in various stages of compression at all
times, resulting in nearly continuous suction and discharge.